Hello

Welcome lekule blog

Hi, I`m Sostenes, Electrical Technician and PLC`S Programmer.
Everyday I`m exploring the world of Electrical to find better solution for Automation.
together in the world. #lekule86
Join us on

Moulding Patterns | Sand Casting Patterns | Patterns And Moulds

Pattern:
Pattern is the solid form that is used to make the mould. Even though a pattern generally resembles the casting being produced, it differs from the casting in terms of certain allowances that are required for producing the correct shape and dimensions and in eliminating some minor details which are too complicated or small to be produced by casting and are left to be produced later by machining.


01-mold-pattern mould


A pattern has to be designed to facilitate moulding and ensure good quality castings. The quality of the castings produced depends on the design of the pattern, its material and construction. A poor casting may result from a good pattern due to various other factors but a poor pattern would never make a good casting.


The design of the pattern depends upon the shape and complexity of the casting, the material of the costing and of the pattern, the type of moulding adopted and the number of castings to be produced.



Types of patterns:

1. Loose pattern

2. Gated pattern

3. Match plate patterns

4. Cope and drag patterns

5. Pattern devices

6. Shell patterns



Loose pattern:


Loose pattern are patterns which are not connected to other patterns or mounted on a plate. Loose patterns may be further classified into:

1. Solid or Single piece pattern

2. Self core pattern

3. Split patterns

4. Loose piece pattern

01-pattern-loose pattern-solid pattern


Solid patterns:


Solid or single piece patterns are the patterns with shapes having straight draft. They are moulded with the entire cavity in one box. The simplest type of solid patterns is the one with a flat base. Such a pattern can be moulded in one box only with flat surface forming the parting line between the two flasks. When using solid patterns the moulder has to cut his own runners, feeding gates and risers which take time. Such patterns are not useful except for limited production. Generally made of wood, these patterns are most inexpensive of all patterns.


01-single piece pattern-solid pattern-loose pattern


Self core patterns:


Self core type solid patterns are patterns having a hollow portion with straight draft which is used for producing its own core during moulding process itself. This type of pattern eliminates the need for core box.


01-self core pattern-core in pattern


Split patterns:


Many patterns cannot be made in a single piece because they have back draft which does not permit their withdrawal. Such patterns are made split into two parts. The pattern is split in such a way that the two parts by themselves have no back draft. One part of the split pattern is molded in the drag and the other in the cope. The pattern parts are held in their relative position by dowel pins so as to ensure proper location of the parts during moulding.


01-split patterns-pattern with loose pieces

Some castings that have complicated shape may require that the pattern is made in three or more parts instead of two. Such split patterns are called multi-piece patterns and require multiple flasks-one flasks for each part of the pattern for moulding.


Patterns with loose pieces:


Some castings require patterns which have parts with back draft in such a way that they cannot be made into split patterns. In these patterns the parts with back draft are made into loose pieces so that the loose pieces can be removed separately from the mould after the main body of the pattern has been removed.

The loose pieces are initially held in a place during moulding with the help of pins or slides but when the main body is withdrawn vertically the loose pieces are left inside the mould. The loose pieces are then withdrawn sideways and pulled up through cavity made up by the main piece. Loose piece patterns have the advantage of a low pattern cost but normal take longer in moulding.


Gated patterns:


Gated patterns are number of loose patterns connected with a gating system. They are moulded like a single pattern and withdrawn from the mould in one piece thus reducing moulding time.


01-gated patterns-lost wax method-lost wax casting


Gated patterns are useful when a number of small castings are to be produced. Of course these patterns do add an extra operation of separating individual castings after they have solidified along with the gating system but the overall time for casting per piece is much lower than if castings were produced individual moulds. Both loose piece patterns and gated patterns are more suited for hand moulding.

01-lost wax method-gated patterns-chess piece manufacturing


Match plate patterns:


These have half mounted on two sides of a pattern plate and aligned with reference to aligning pins on the plate. They are designed to work with match plate moulding machines for high production rates. The two halves of the mould are made with the pattern halves on the two sides of the pattern plate and assembled the two mould halves match.
Match plate patterns are expensive but their cost can be justified if the quantity of production is large. Because the moulding is done on machines, match plate patterns produce castings which are more accurate than those produced by hand moulding.


01-match plate patterns-split patterns-split pattern with loose pieces



Cope and drag patterns:


As the size of the castings increases, it becomes more and more difficult to handle match plates. For medium and large size castings separate pattern plates are made for the cope and drag halves. The pattern halves are geometrically located with reference to aligning pins or holes in the pattern plates for proper matching.

The cope and drag are separately made, may be on different moulding machines by different workers and assembled with proper matching for pouring.

01-cope and drag-sand casting patterns-sand casting flasks


Pattern devices:


When the size of the casting is too large and the number required is only one or two, full patterns generally prove uneconomical. Pattern devices like sweeps, segments, skeletons and follow boards are used in such cases to save on pattern cost.


01-sweep pattern-sweep pattern in casting-pattern devices


Shell patterns:


Shell patterns are used mostly for piping work or for producing drainage fittings. This pattern consists of a thin cylindrical or curved metal piece parted along the center line. The two halves of the pattern are held in alignment by dowels. The outside surface of the pattern is used to make the mould for the fitting required while the inside can serve as a core box.


01-pattern allowance-pattern draft-plastic core box

Share this:

ABOUTME

Hi all. This is deepak from Bthemez. We're providing content for Bold site and we’ve been in internet, social media and affiliate for too long time and its my profession. We are web designer & developer living India! What can I say, we are the best..

Post a Comment
My photo

Hi, I`m Sostenes, Electrical Technician and PLC`S Programmer.
Everyday I`m exploring the world of Electrical to find better solution for Automation. I believe everyday can become a Electrician with the right learning materials.
My goal with BLOG is to help you learn Electrical.

Labels

LEKULE TV EDITORIALS ARTICLES DC ROBOTICS DIGITAL SEMICONDUCTORS GENERATOR AC EXPERIMENTS MANUFACTURING-ENGINEERING REFERENCE FUNDAMENTAL OF ELECTRICITY ELECTRONICS ELECTRICAL ENGINEER MEASUREMENT TRANSDUCER & SENSOR VIDEO ARDUINO RENEWABLE ENERGY AUTOMOBILE TEARDOWN SYNCHRONOUS GENERATOR DIGITAL ELECTRONICS ELECTRICAL DISTRIBUTION CABLES AUTOMOTIVE MICROCONTROLLER SOLAR PROTECTION DIODE AND CIRCUITS BASIC ELECTRICAL ELECTRONICS MOTOR SWITCHES CIRCUIT BREAKERS CIRCUITS THEORY PANEL BUILDING ELECTRONICS DEVICES MIRACLES SWITCHGEAR ANALOG MOBILE DEVICES WEARABLES CAMERA TECHNOLOGY COMMUNICATION GENERATION BATTERIES FREE CIRCUITS INDUSTRIAL AUTOMATION SPECIAL MACHINES ELECTRICAL SAFETY ENERGY EFFIDIENCY-BUILDING DRONE CONTROL SYSTEM NUCLEAR ENERGY SMATRPHONE FILTER`S POWER BIOGAS BELT CONVEYOR MATERIAL HANDLING RELAY ELECTRICAL INSTRUMENTS ENERGY SOURCE PLC`S TRANSFORMER AC CIRCUITS CIRCUIT SCHEMATIC SYMBOLS DDISCRETE SEMICONDUCTOR CIRCUITS WIND POWER C.B DEVICES DC CIRCUITS DIODES AND RECTIFIERS FUSE SPECIAL TRANSFORMER THERMAL POWER PLANT CELL CHEMISTRY EARTHING SYSTEM ELECTRIC LAMP FUNDAMENTAL OF ELECTRICITY 2 BIPOLAR JUNCTION TRANSISTOR 555 TIMER CIRCUITS AUTOCAD BLUETOOTH C PROGRAMMING HOME AUTOMATION HYDRO POWER LOGIC GATES OPERATIONAL AMPLIFIER`S SOLID-STATE DEVICE THEORRY COMPUTER DEFECE & MILITARY FLUORESCENT LAMP INDUSTRIAL ROBOTICS ANDROID ELECTRICAL DRIVES GROUNDING SYSTEM CALCULUS REFERENCE DC METERING CIRCUITS DC NETWORK ANALYSIS ELECTRICAL SAFETY TIPS ELECTRICIAN SCHOOL ELECTRON TUBES FUNDAMENTAL OF ELECTRICITY 1 INDUCTION MACHINES INSULATIONS USB ALGEBRA REFERENCE HMI[Human Interface Machines] INDUCTION MOTOR KARNAUGH MAPPING USEUL EQUIATIONS AND CONVERSION FACTOR ANALOG INTEGRATED CIRCUITS BASIC CONCEPTS AND TEST EQUIPMENTS DIGITAL COMMUNICATION DIGITAL-ANALOG CONVERSION ELECTRICAL SOFTWARE GAS TURBINE ILLUMINATION OHM`S LAW POWER ELECTRONICS THYRISTOR BOOLEAN ALGEBRA DIGITAL INTEGRATED CIRCUITS FUNDAMENTAL OF ELECTRICITY 3 PHYSICS OF CONDUCTORS AND INSULATORS SPECIAL MOTOR STEAM POWER PLANTS TESTING TRANSMISION LINE C-BISCUIT CAPACITORS COMBINATION LOGIC FUNCTION COMPLEX NUMBERS CONTROL MOTION ELECTRICAL LAWS INVERTER LADDER DIAGRAM MULTIVIBRATORS RC AND L/R TIME CONSTANTS SCADA SERIES AND PARALLEL CIRCUITS USING THE SPICE CIRCUIT SIMULATION PROGRAM AMPLIFIERS AND ACTIVE DEVICES APPS & SOFTWARE BASIC CONCEPTS OF ELECTRICITY CONDUCTOR AND INSULATORS TABLES CONDUITS FITTING AND SUPPORTS ELECTRICAL INSTRUMENTATION SIGNALS ELECTRICAL TOOLS INDUCTORS LiDAR MAGNETISM AND ELECTROMAGNETISM PLYPHASE AC CIRCUITS RECLOSER SAFE LIVING WITH GAS AND LPG SAFETY CLOTHING STEPPER MOTOR SYNCHRONOUS MOTOR AC METRING CIRCUITS BECOME AN ELECTRICIAN BINARY ARITHMETIC BUSHING DIGITAL STORAGE MEMROY ELECTRICIAN JOBS HEAT ENGINES HOME THEATER INPECTIONS LIGHT SABER MOSFET NUMERATION SYSTEM POWER FACTORS REACTANCE AND IMPEDANCE INDUCTIVE RECTIFIER AND CONVERTERS RESONANCE SCIENTIFIC NOTATION AND METRIC PREFIXES SULFURIC ACID TROUBLESHOOTING TROUBLESHOOTING-THEORY & PRACTICE 12C BUS APPLE BATTERIES AND POWER SYSTEMS DC MOTOR DRIVES ELECTROMECHANICAL RELAYS ENERGY EFFICIENCY-LIGHT INDUSTRIAL SAFETY EQUIPMENTS MEGGER MXED-FREQUENCY AC SIGNALS PRINCIPLE OF DIGITAL COMPUTING QUESTIONS REACTANCE AND IMPEDANCE-CAPATIVE SEQUENTIAL CIRCUITS SERRIES-PARALLEL COMBINATION CIRCUITS SHIFT REGISTERS WIRELESS BUILDING SERVICES COMPRESSOR CRANES DIVIDER CIRCUIT AND KIRCHHOFF`S LAW ELECTRICAL DISTRIBUTION EQUIPMENTS 1 ELECTRICAL DISTRIBUTION EQUIPMENTS B ELECTRICAL TOOL KIT ELECTRICIAN JOB DESCRIPTION INDUSTRIAL DRIVES LAPTOP SCIENCE THERMOCOUPLE TRIGONOMENTRY REFERENCE UART oscilloscope BIOMASS CONTACTOR ELECTRIC ILLUMINATION ELECTRICAL SAFETY TRAINING ELECTROMECHANICAL FEATURED FILTER DESIGN HARDWARE JUNCTION FIELD-EFFECT TRANSISTORS NASA NUCLEAR POWER VALVE COLOR CODES ELECTRIC TRACTION FLEXIBLE ELECTRONICS FLUKE GEARMOTORS INTRODUCTION LASSER PID PUMP SEAL ELECTRICIAN CAREER ELECTRICITY SUPPLY AND DISTRIBUTION MUSIC NEUTRAL PERIODIC TABLES OF THE ELEMENTS POLYPHASE AC CIRCUITS PROJECTS REATORS SATELLITE STAR DELTA VIBRATION WATERPROOF